Duplex-pressure emergency-brake.



. HEDENDAHL.

Patented July 27, 1909.

"EVEFLZZ 22 W DUPLEX PRESSURE EMERGENCY BRAKE.

APPLICATION-FILED NOV. 20, 1906.

%WITNESSES at Denver, in the county of State of Colorado, have invented new and,

NITED sTArns Pt TENT OFFICE.

THEODORE A. HEDENDAHL, OF DENVER, COLORADO, ASSIGNOR TO THE WESTINGHOUSE AIR BRAKE COMPANY, OF PITTSBURG, PENNSYLVANIA, A CORPORATION OF PENN- SYLVANIA.

DUPLEX-PRESSURE EMERGENCY-BRAKE.

Specification of Letters Patent.

Patented July 27, 1909.

Application filed November 20, 1906. Serial No. 344,210.

To allwhom it may concern:

Be it known that I, THEODORE A. HEDEN- DAIIL, a citizen of the United States, residing Denver and useful Improvements in Duplex Pressure Emergency-Brakes, of which the following is a specification.

- apparatus, wherein themaximum degree of This invention relates to combined straight air service and automatic emergency brake pressure admitted to thebrake cylinder in direct service applications is limited to a predetermined amount, While in emergency ap*-,

plications the automatic valve device operates to supply air at a greater maximum pressure to the brake cylinder.

This form of equipment is especially adapt.-

ed to be'employed in traction service, such as electric cars, where the cars are sometimes operated singly, and at other times'in trains motor car and trailer, and the principal obof two or three cars, "either motor cars 'or'a ject of my present invention is to provide improved means for limiting the maximum degree of pressure which may be supplied by the motorma/ns brake valve to the straight airpipe in service applications. And an.- other ob ect 1s to provide an additional connection for reservoirpressure 1n order to re lease the brakes after an automatic emergency application.

In the accompanying drawing; Flgure 1 1s a dlagrammatic elevation of a car brake equipment embodying one form of my im provement; F1g.--2 a similar diagrammatic View of a portion of saidapparatus on a larger scale, the valve mechanism being 4 shown in vertical section; Fig. 3 a lan view of the seat of the motormans bra e valve; and Fig. '4 a face view of the rotary valve.

. As shown in the drawing, the apparatus comprises a main reservoir 5, which may be charged with compressed air from any suitable source, such as a motor driven pump 6, a motormans brake valve 11, preferably one at-each end of the car, for controlling the supply of air to the train pipe 13-leading to the automatic emergency valve 15, and the straight air ipe 12 leading directly to the brake cylin er 14 through the emergency valve. This emergency valve is also connected with the main reservoir through pipe 7. A check valve 16 may be provided in the pipe 7 near the main reservoir, and the train pipe and straight air pipe are prefera'bly eX- tended to the ends of the car where they have the usual cocks and couplings forconnection with similar pipes on adjacent cars when the same are coupled up in a train.

According to my improvement means, such as a reducing valve 10, are inserted between the reservoir su ply or pipe-7, and a connection or pipe 8 leading to the brake valve 11 for limlting the maximum degree of pressure which may be admittedv to the strai ht air pi e to a predetermined amount which is less t an the normal degree carried in the main reservoir. This reducing valve may beof any desired construction, that shown in Fig. 2 being of the standard slide valve type, which is well known in the art.

In order to provide sufiicient volume of air at the desired reduced maximum degree of pressure I prefer to employ a service resertrain pipe pressure in emergency applications, the higher reservoir pressure acting on the piston moves the valve to cut off communication from the straight air pipe to the brake cylinder and to 0 en communication from the main reservoir t rough port SO into the brake cylinder, thereby applying the brakes with the maximum degree of pressure.

As shown in Figs. 2, 3 and 4, the motormans brake valve has a seat containing ports 17,- 18, 19, and 21 communicating respectively with the pipes S, 12, 13 and 7, r-yhile the rotary valve 22 is provided with through ports 23 and 26 and cavities 24 and 25. a p When in its normal or release position, as

' valve 22.

' limited to a I claim as new and desire to secure by Letters the slide valve 28 to its normal position conshown in Fig. 2, air at the reduced pressure, as determined by the adjustment of the feed or reducing valve 10, flows into service reservoir 9 and through pipe 8 through ports 17 and 23 into the chamber above the rotary At the same time the brake cylin der is discharged to the atmosphere through straight air pipe 12, ort 18, cavity 24, and exhaust port 20, w ile the train pipe is charged with under pressure from the main reservoir through an additional branch of the pipe 7, port 21, cavity 25, andport 19, communicating with pipe 13.

In making an ordinary service application of the brakes, the brake valve is turned to a position for closing the exhaust'and registermg ports 26 and 18, the port 17 st1ll being connected to port 23, air flows through the straight air pipe 12 to the brake cylinder. T he service reservoir 9 affords a suflicient volume to draw from and the reducing valve device limits the maximum brake cylinder pressure obtainable in service applications to the desired predetermined amount less than the maximum main reservoir pressure.

When a sudden reduction is made in train pipe pressure for an emergency application,

either automatically by a break-in-two, or by 0 ening a conductors valve, or byturning i t e brake valve to a position in which the cavity 24 connects the train pipe port 19 with the exhaust port 20, the piston 27 oper ates the valve 28 to cut off communication from the straight'air pipe and opens communication from the main reservoir tothe brake cylinder through port 30, whereby the air at t e higher main reservoir pressure equalizes into the brake cylinder and ap lies the brakes with greater force than is o tainable in service applications. 4 i

In order to release the brakes after'an' emergency application, the brake valve is returned to normal .position, whereupon air under pressure from the main reservoir equalizes through ports 21, 25, 19 and train plpe 13 on the piston 27 of the emergency va ve device, and the spring 31 then returns necting port 30 to the straight air pipe 12 and allowing the air from the brake cylinder to exhaust through ports 18, 24 and 20 in'the' brake valve.

It will now be seen that myimprovement has the advantage of providing a duplex pressure control of the brakes, in which the maximum pressure in service applications is redetermined desired degree, while a much igher degree of braking pressure is applied in emergency applications.

Having now described my invention, what Patent, is

1. Inafluid pressure brake,the combination with a train pipe, a reservoir, a brake cylinder, a straight air pipe, and a motormans brake valve for controlling the supply of air from. the reservoir to the straight air pipe, of a reducing valve between the reservoir supply and the brake valve for limiting the degree of brake cylinder pressure in service applications, and an automatic valve device normally establishing communication from "he straight air pipe to the brake cylinder, but operating under a reduction in train pipe pressure to cut off said communication and to 0 en communication from the reservoir to the brake cylinder.

2.. In a fluid pressure brake, the combinationwith a main reservoir, train pipe, service reservoir, straight air pipe, brake cylinder, and a brake valve for controlling the supply of air from the service reservoir to the straight air pipe, of a reducing valve between the main reservoir and service reservoir, and an automatic valve device normally establishing communication from the straight air pipe to the brake cylinder, but operating under a sudden reduction in train pipe pressure to close said communication and to open communication from the main reservoir to the brake cylinder. I

3. In a fluid pressure brake, the combination with a reservoir, train pipe, brake cylinder, straight air pipe, and a brake valve for controlling the supply of air from the reservoir to the straight air pipe, of a reducing valve between the reservoir supply and the brake valve, an additional connection from the reservoir to the brake valve, and an automatic valve device adapted to operate under a sudden reduction in train pipe pressure to open direct communication from the reservoir to the brake cylinder.

4. In a fluid pressure brake, the combination with a reservoir, train pipe, straight air pipe, brake cylinder, and a reducing valve, of

a brake valve having means for controlling the supply of air from the reducing valve to the straight air pipe, and from thereservoir to the train pipe, and an automatic valve device operating under a sudden reduction in train pipe pressure to open communication from the reservoir to the brake cylinder.

5. In a fluid pressure brake, the combination with a mam reservolr, train pipe, serv ice reservoir, straight air pipe, brake cylinder, and a reducing valve between main reservoir and service reservoir, of a brake valve having connection with the main reservoir, service reservoir, train pipe, and straight air pipe, and an automatic valve device operating under a sudden reduction in train pipe pressure to open communication from the main reservoir to thebrake cylinder.

6. In a fluid pressure brake, the combination with a source. of fluid pressure, train pipe, brake cylinder and a brake valve for supplying air to the brake cylinder, of a reducing valve between the source of pressure and the brake valve, and a valve device oper- 928,976 i v a ated by variations in train pipe pressure for ing air to the brake cylinder and a brake s supplying air directly from the source of valve for supplying air from said reducing pressure to the brake cylinder. l valve directly to the brake cylinder.

'7. In a fluid pressure brake, the combina- In testimony whereof I have hereunto set tion with a train pipe, brake cylinder, resermy hand.

voir, and reducing valve for limiting the THEODORE A. HEDENDAHL. pressure offluid supplied from the reservoir, Witnesses:

of an automatic valve device operated by a ARTHUR JOHNSON,

reduction in train pipe pressure for supply- W. S. BARTHOLOMEW. 

